Background: Elbows are important constituent parts of piping systems in nuclear power plant.The pressure boundary integrity of elbows direct influences reliability of nuclear power plant operation.Purpose: Therefore

it is necessary to carry out analysis of the cracked elbows to evaluate whether the safety requirement is satisfied.Methods: The principal fracture mechanics parameters required in analysis and evaluation are stress intensity factor K and J integral.The most important procedure for calculating fracture parameters K/J is to build up correct and reasonable mesh using finite element method.Results: In this paper

a fast programmed and partitioned three dimensional modeling procedure was proposed

which is useful to model the complex finite element model in fracture mechanics calculation

and calculation case of KJ of cracked elbows which subjected to inner pressure and in-plan moment was given based on the modeling method.Conclusions: The results prove that the programmed and partitioned modeling method developed in this paper could solve the complex modeling issue in fracture mechanics calculation of cracked elbow

as well as offer experiences for modeling other cracked components and calculating fracture mechanics parameters KJ.